JPH0326726A - Carbon short fiber aggregate and fiber-reinforced thermoplastic resin composition using same - Google Patents

Abstract

PURPOSE:To provide the subject aggregate improved in the electrical characteristics thereof by the addition of a small amount of carbon black without deteriorating the physical properties and useful for preventing the static electrification of OA equipments, etc., by preliminarily adhering the carbon black to the surfaces of fibers in a specific ratio. CONSTITUTION:The objective aggregate comprises (A) a carbon short fiber aggregate coated with (i) a sizing agent in an amount of 0.1-10wt.% based on the whole amount of (ii) the carbon short fibers is subjected to an adhesion of (B) carbon black in an amount of 0.5-5% based on the whole amount of the component. The component (i) includes epoxy compounds comprising 55-95wt.% of an epoxy compound liquid at room temperature and 5-45wt.% of an epoxy compound in solid form at room temperature.

Description

[Detailed description of the invention] (Industrial application field) The present invention provides short carbon fiber aggregates and reinforcement/reinforcement thereof. The present invention relates to a fiber-reinforced thermoplastic resin composition used as a material.

(Prior art) In recent years, fiber-reinforced resin compositions made by mixing and dispersing short carbon fibers in various matrices have been developed to have high strength, high rigidity, low specific gravity, high electrical conductivity, low coefficient of thermal expansion, and high durability. It is attracting attention as an industrially important material because it has excellent features such as abrasion resistance.

Particularly recently, there has been a demand for fiber-reinforced resin compositions that are electrically conductive while maintaining mechanical properties for antistatic and electromagnetic shielding of office automation equipment, gears, and the like.

Generally, carbon fibers are mixed into various matrices such as polyester, polyamide, polyolefin, acrylic resin, epoxy resin, and phenolic resin. When dispersing to obtain a fiber-reinforced resin material, a large number of short carbon fibers are aggregated in advance using a sizing agent, etc., in order to make the short carbon fibers easier to handle and improve workability in the mixing and dispersion process. ing. Various such sizing agents are known, and for example, matrix resins such as those described above are commonly used. However, with conventional short carbon fiber aggregates, the aggregation is not sufficient and there are various problems in the mixing and dispersion process into the Mato-17x resin. This method has disadvantages such as clogging in the feeding process or inability to uniformly disperse fibers in the IJ box.

Therefore, in order to solve various problems in the process of mixing and dispersing into Max.
g/l or more, short carbon fiber chips with an angle of repose of 0 or less (
Techniques have been proposed, such as using Japanese Patent Application Laid-open No. Sho A/-AAI, No. 1A).

(Problems to be Solved by the Invention) However, various problems in the conventional process of mixing and dispersing into a matrix resin have not been improved in the carbon short fiber chips disclosed in Japanese Patent Application Laid-Open No. 1997-6AA/A. However, as a fiber-reinforced resin composition, it has not yet been able to exhibit sufficient mechanical and electrical properties, and further improvements have been desired.

(Means for Solving the Problems) Therefore, the present inventors not only improved various problems in the process of mixing and dispersing carbon fibers into a matrix resin, but also improved the mechanical properties and electrical properties of a fiber-reinforced resin composition. As a result of intensive studies to simultaneously improve the sizing agent and carbon black, the inventors discovered that the above problems could be solved by blending a thermoplastic resin with an aggregate of short carbon fibers coated with a specific amount of sizing agent and carbon black, and thus arrived at the present invention. . Conventionally, carbon black is added to thermoplastic resins to improve electrical properties, but in the present invention, by adding carbon black along with short carbon fibers, it is possible to improve mechanical and electrical properties with a small amount that was previously unimaginable. A resin composition has been obtained.

That is, an object of the present invention is to provide an aggregate of short carbon fibers that has excellent workability when producing a fiber-reinforced resin composition and that allows the resulting resin composition to exhibit excellent mechanical properties and electrical properties. The object of the present invention is to provide a resin composition having extremely excellent mechanical properties and electrical properties by combining such an aggregate and a thermoplastic resin.

The contents are (1) sizing agent added to the total amount of carbon short fibers,
/~IO weight% surface-coated short carbon fiber aggregate, and carbon black is added to the total amount of carbon short fibers at θ. &-5% by weight of carbon short fiber aggregate, (2) Carbon short fiber aggregate whose surface is coated with 0,/~/θ weight% of sizing agent based on the total amount of carbon short fibers. and the carbon black has an O. This can be easily achieved by using a fiber-reinforced thermoplastic resin composition comprising /-jθ parts by weight of short carbon fiber aggregates having % by weight of S-S attached to 100 parts by weight of a thermoplastic resin.

The present invention will be explained in detail below.

In the present invention, the surface of the short carbon fibers is coated with a sizing agent and aggregated. Generally, any sizing agent can be used as the sizing agent, and one that provides good convergence of monofilaments can be selected. Sizing agents used in the present invention include, for example, epoxy compounds, saturated or unsaturated polyesters, polyphenylene sulfide, polyphenylene ether, polycarbonate, l-'IJ oxymethylene, polysterene, polyolefins, acrylic resins, acetic acid. Examples include homopolymers or copolymers such as vinyl resins and polyamide resins. Specifically, epoxy compound g! which is liquid at room temperature. ;-9A; Weight % and epoxy compound solid at room temperature &-! ．． Preferred are epoxy compounds that turn red from 1% by weight, water-soluble polyamide compounds, and the like. Additionally, surfactants, silane coupling agents, epoxy curing agents, catalysts, adhesives, etc. may be added as necessary. The amount of the sizing agent used at this time is θ relative to the total amount of short fibers. 1 to io weight %, preferably O. S~7
Selected in a range of weight %. The surface coating method includes, for example, impregnating a number of carbon fibers with a sizing agent and then drying them. The sizing agent used for surface coating may be a solvent or the like (j'! or contains a sizing agent. :'l: -i'' using a sizing agent 4).The solvent used is C: Examples include 2-butanone, dihydrofuran, N,N-dimethylformamide, acetone, chloropol, dichloromethane, etc. Surfactants used in emulsion include, for example, castor of poly-3-he-cymethylene. A small number of <h4l)i types selected from oil ethers, nord-fuel ethers, polyoxyethyl-1,/-alkyls-1-ter of styrene phenyl ether, polyoxyethylene alkylallyl ethers, bovar, etc. The following surfactants can be mentioned. If the adhesion amount of the sizing agent is less than 71'-θ,/wt%, the convergence of the short carbon fiber aggregate will be poor, and if the adhesion amount exceeds lθ, the physical properties of the short carbon fiber-reinforced thermoplastic resin will deteriorate.
Second, I don't like it.

Next, consider the method of adding carbon plaque and the temperature is L'r? Basic fiber 1 claw 1 rising agent turret cloth for elementary and middle school 7 years I. There is a method in which carbon black is dispersed in a numeric agent and the yarn U is added thereto, but the latter method is the most effective. 3, which is more effective than water, has an additive effect of O. S=S
The weight percent preference is θ. , Yuichi. It is better to set it to 7%. As the carbon black to be used, any known carbon black, carbon black, carbon black, carbon black, etc. can be used. A conductive carbon block exclusively for use in terrane black or by-product carbon black, with a specific thorn area of 60% or more, preferably more than tθθ,r?/9', can also be used. The color is preferable for the expression of the subject matter.

Carbon single fiber aggregate of the present invention &'. t % σ] as 1,' (Although other physical properties include a force of repose angle S゛θ゛ or less, preferably 4'!' or less: Good.

If it deviates from this range, the dry blendability and extrudability of the short carbon fiber aggregate L'matrix resin & will deteriorate, so it is preferable that L<t. It's ugly.

Various conventionally known carbon fibers can be used as the carbon fibers used in the present invention. Specific examples of carbon fibers include polyacrylonitrile, resin, Pictite, polyvinyl alcohol, etc. After coating the surface of these carbon fibers, a known cutting method is used to cut the carbon fiber to length/=2θ, preferably 2《 ．． 7
-/O mir It is best to cut it and use it.

Next, a fiber reinforced resin composition using such a short carbon fiber aggregate as a reinforcing material will be explained.

Examples of thermoplastic resins used include polycarbonate, polysterene, polyester, polyolefin, acrylic resin, polyoxymethylene, polyphenylene sulfide, polyphenylene ether, polyphenylene oxide, polybutylene terephthalate, polyether ether ketone, polyphenylene sulfone, and fluorine. Known thermoplastic resins such as polymers such as resins or copolymers thereof can be mentioned, and preferably polycarbonate, polyoxymethylene, polybutylene 17 phthalate 1, polyphenylene oxide, polyphenylene sulfur oxide, etc. are used. good.

The thermoplastic resin composition of the present invention contains these components.
This blending ratio and L2 are, for thermoplastic resin lOθ weight part κ, short carbon fiber aggregate/~SO overlapped part, preferably L, <=3·~aO overlapped part, Further, carbon black in short carbon fibers is o. r-. t% by weight preferably θ. A good value is 5 to 3% by weight. If the short carbon fiber aggregate is less than / part by weight of the thermoplastic resin/θθ, the reinforcing effect of carbon fibers will not be exhibited, while if it exceeds 50 parts by weight of the thermoplastic resin lOθ, the matrix resin Various problems occur during the mixing and dispersion process. In addition, the amount of carbon blank in the short carbon fiber is θ. If the S content is less than 5% by weight, the conductivity will not be improved and 5% by weight κ
If it exceeds this value, the conductivity will be improved, but the mechanical properties will be lowered and the thread focusing will be lowered, resulting in a marked decrease in workability.

Further, the method of blending such a thermoplastic resin, the short carbon fiber aggregate of the present invention, and carbon black is not particularly limited, but is usually performed using a single screw extruder, a twin screw extruder, a press machine, or a high-speed mixer injection molding method. This is done by a method such as a machine, a drawing machine, or a shaping machine.

In addition to the above-mentioned components, other short and long fibers such as carbon fibers, glass fibers, aramid fibers, boron fibers, silicon carbide fibers, whiskers, nickel, aluminum, etc. may be added to the extent that the effects of the present invention are not impaired. Adding reinforcing agents such as metal coatings such as copper, fibrous reinforcing materials, or fillers such as carbon plaque, molybdenum disulfide, mica, Merck, and calcium carbonate, stabilizers, lubricants, and other additives such as 2a agents. Can be done.

(Example) Next, the present invention will be explained in more detail with reference to Examples. still,
Each physical property was measured as follows.

(1) Angle of repose of carbon short fiber aggregate Approximately 309 short carbon fiber aggregates are gradually dropped from a height of 10 (Ml), and the inclination angle of the piled up pile is determined.

(2) Physical properties of molded products The physical properties of molded products are measured in accordance with the following methods.

Tensile strength: ASTM method [) 1,3t volume resistivity:
SRIS method SRIS2.7o/Example/ (4) Production of short carbon fiber aggregate Pitch-based long carbon fiber ("Dialead K223. Manufactured by Mitsubishi Chemical Corporation") t, ooo book "Epicoat" r3lI (manufactured by Shell Chemical Co., Ltd.) Carpon black ("Diablack" + 39!; OB, manufactured by Mitsubishi Kasei ■) was added to an emulzidine solution (1!1% by weight, 3% by weight) of 60 parts by weight and 0 parts by weight of 1 Epikote''/00lI (manufactured by Shell Chemical Co., Ltd.). ) i. After impregnating 0 parts by weight into a liquid dispersed in a paint shaker, the mixture was heated and dried at about 10° C. for 0 minutes, and then a short carbon fiber aggregate of btaI length was produced using a cutter.

The amount of epoxy compound attached to the obtained short carbon fiber aggregate was 3
．． It was 7% by weight.

After dry blending 20 parts by weight of the carbon short fiber aggregate and 5 parts by weight of dried polyoxymethylene resin pellets "Duracon" M9θ-02, manufactured by Polyplastics Co., Ltd., The mixture was poured into a screw extruder, melt-mixed, extruded into strands, cooled with water, and then cut into pellets.Charging into the extruder was smooth, and the short carbon fiber aggregate and resin were uniformly dispersed.

What about the short carbon fiber reinforced molding material obtained in this way? θ
After drying for .degree. C.ti hours, the sample was molded by injection molding to obtain a test piece.

Example (4) Production of short carbon fiber aggregate Binote-based long carbon fibers (''Dialead K223, manufactured by Mitsubishi Kasei ■) 6θoo were mixed with carbon black ('' Diablack "◆393θB, manufactured by Mitsubishi Kasei■)/.ON" was impregnated in a paint shaker dispersed solution, and then approximately 20%
The mixture was heated and dried at ℃ for 2Q minutes, and then a 6-length carbon short fiber aggregate was produced using a cutting machine.

The amount of water-soluble polyamide adhered to the obtained short carbon fiber aggregate was 3.0% by weight.

■ Production of short carbon fiber reinforced molding material After dry blending 20 parts by weight of the carbon fiber aggregate and parts by weight of dried polyoxymethylene resin pellets "Duracon" M90 (manufactured by Polyplastics), The mixture was poured into a screen extruder, melt-mixed, extruded into strands, cooled with water, and then cut into pellets. Feeding into the extruder was smooth, and the short carbon fiber aggregate and resin were uniformly dispersed.

The carbon short fiber reinforced molding material obtained in this way was
After drying for 0'(: f hours), it was molded by injection molding to obtain a test piece.

Comparative Example / ■ Production of carbon short fiber aggregate Pitch-based carbon long fiber (“Dialead” K223 manufactured by Mitsubishi Chemical Co., Ltd.) 6θθ body 1 Ebicord 'g3da (-/' manufactured by L Kagaku Co., Ltd.) 6θ weight parts and 'Epicord''゜／0011(
Shell Chemical Co.) 4/! Carbon black ("Diablack" ◆39s θB, manufactured by Mitsubishi Kasei ■) θ. /and/θ.
After impregnating 0 parts by weight into a liquid dispersed in a paint shaker, the mixture was heated and dried for λθ minutes at about 7209° C., and then a 6 m× length carbon short fiber aggregate was produced using a cutting machine.

The amounts of epoxy compound deposited on the obtained short carbon fiber aggregates were 3.7 and 2.6 weight, respectively.

Polyoxymethylene resin beret, “Duracon” M9
0102 (manufactured by Polyplastics Co., Ltd.) in weight parts, the mixture was poured into a screen extruder, melt-mixed, extruded into a stock shape, cooled with water, and cut into pellet shapes. Feeding into the extruder was smooth, and the short carbon fiber aggregate and resin were uniformly dispersed.

The short carbon fiber-reinforced molding material obtained in this manner was dried for a period of θ°Ctt, and then molded by injection molding to obtain a test piece.

Comparative Example 2 (4) Production of short carbon fiber aggregate Pitch-based carbon long fibers (''Dialead'' K223. manufactured by Mitsubishi Kasei ■) were mixed with ``Ebicoat'' G3ti (
Shell Chemical Co. #) 40ft volume and 1 epicoat"/0θ
After impregnating it in an emulsion solution (concentration: 3% by weight) with Q (Shell Chemical Co., Ltd.), approximately /. 2
It was heated and dried at 0° C. for 20 minutes, and then a carbon fiber aggregate of length A was produced using a cutting machine.

The amount of epoxy compound attached to the obtained short carbon fiber aggregate was 3
．． It was 3% by weight.

(Production of short carbon fiber reinforced molding material) The above short carbon fiber aggregate, 20 parts by weight, 1 dried polyoxymethylene resin pellet, 1 Duracon M90,
(manufactured by Polyplastics Co., Ltd.) and tθ weight part, the mixture was poured into a screw extruder, melt-mixed, extruded into a strand shape, cooled with water, and then cut into a pellet shape. Feeding into the extruder was smooth, and the short carbon fiber aggregate and resin were uniformly dispersed.

90% of the carbon short fiber-reinforced material obtained by 5KL
After drying for .degree. C.y hours, it was molded by injection molding to obtain a test piece.

Comparative Example 3 (4) Production of short carbon fiber aggregate Pitch-based long carbon fibers (Dialead'K223, manufactured by Mitsubishi Kasei ■) 60θQ pieces were mixed with a water-soluble polyamide aqueous solution (!
After impregnating it once in 3 layers (i%). approx./20 at 20℃
The mixture was dried by heating for a minute, and then a 6-length carbon short fiber aggregate was produced using a cutting machine.

The amount of water-soluble polyamide deposited on the obtained short carbon fiber aggregate was determined by J. θ weight was ~.

0 Manufacture of carbon short fiber reinforced or shaped material 20N parts of the short carbon fiber aggregate and 1 part by weight of the dried polyoxymethylene resin pellet 1 part by weight of Duracon "M9θ1θCo, Bot Plastics Co., Ltd.ff)" were dried. After blending, the mixture was poured into a screw extruder, melt-mixed, extruded into strands, cooled with water, and cut into pellets.

Feeding into the extruder was smooth, and the short carbon fiber aggregate and resin were uniformly dispersed.

What about the short carbon fiber reinforced molding materials obtained in this way? θ
After drying for Cu hours, it was molded by injection molding to obtain a test piece.

Table 7 shows the extrudability and mechanical properties of Examples/~2 and Comparative Examples/~.

(Effects of the Invention) The short carbon fiber aggregate of the present invention allows conductive carpump thick to exist on the fiber surface in advance, so that the short carbon fiber reinforced resin composition can be added in a small amount of carbon black, which was previously unthinkable. Improved electrical characteristics. Moreover, because the purpose can be achieved with a small amount of carbon black added, the mechanical properties of the molded product do not deteriorate due to the conventional addition of force bomb black, and the mechanical properties of the molded product show extremely good values, making it suitable for industrial use. Extremely useful.

Claims (2)

[Claims] (1) Add a sizing agent of 0.1 to 0.1 to the total amount of short carbon fibers.
A 10% by weight surface-coated short carbon fiber aggregate,
In addition, carbon black is added at a rate of 0.5 to the total amount of short carbon fibers.
A carbon short fiber aggregate characterized in that it is formed by adhering to ~5 weight. (2) Add a sizing agent of 0.1 to 0.1 to the total amount of short carbon fibers.
A 10% by weight surface-coated short carbon fiber aggregate,
In addition, carbon black is added at a rate of 0.5 to the total amount of short carbon fibers.
~5% by weight of carbon short fiber aggregates attached to thermoplastic resin 1
A fiber-reinforced thermoplastic resin composition containing 1 to 50 parts by weight per 00 parts by weight.